MQ-7 Carbon Monoxide Gas Sensor

The MQ-7 Carbon Monoxide Gas Sensor is a semiconductor gas sensor that detects the presence of Carbon Monoxide gas at concentrations from 10 ppm to 10,000 ppm. The sensor’s simple analog voltage interface requires only one analog input pin from your microcontroller.

The MQ-7 Carbon Monoxide Gas Sensor detects the concentration of Carbon Monoxide gas in the air and ouputs its reading as an analog voltage. The sensor can operate at temperatures from -10 to 50°C and consumes less than 150 mA at 5 V.

Connections

Connecting five volts across the heating (H) pins keeps the sensor hot enough to function correctly. Connecting five volts at either the A or B pins causes the sensor to emit an analog voltage on the other pins. A resistive load between the output pins and ground sets the sensitivity of the detector.The resistive load should be calibrated for your particular application using the equations in the datasheet, but a good starting value for the resistor is 20 kΩ.